1. Field
Example embodiments relate to a structure having a structural tube, at least one cross member, and an end plate. Example embodiments also relate to a method of fabricating the structure. Example embodiments also relate to a system having the structure.
2. Description of the Related Art
In the conventional art, plates are often secured to an end of a structural tube in order to attach the structural tube to another structural member or to anchor the tube to the ground. FIG. 1, for example, illustrates an example of an end plate 10 attached to an end of a structural tube steel member 15. In the conventional art, the structural tube steel member 15 is attached to the end plate 10 by welding. For example, an all around fillet weld, a stitch weld, a two-sided fillet weld, three-sided fillet weld, or a four-sided fillet weld applied at the interface between the structural tube steel member 15 and the end plate 10 may be provided to secure the structural tube steel member 15 to the end plate 10.
In general, an end plate may include a plurality of holes through which connecting members, for example, bolts, may pass. For example, in FIG. 1 the end plate 10 includes four holes 20 (three of which are illustrated) arranged near corners of the end plate 10. FIG. 2 is an example of the conventional end plate 10 secured to a concrete foundation 30 via a plurality of anchor bolts 25. Although not shown in FIG. 2, the anchor bolts 25 could be substantially L-shaped or J-shaped or could include a flared end to ensure the bolts are not easily removed from the foundation 30.
In the conventional art, stiffeners may be employed to stiffen the base of tube steel members. FIG. 3, for example, illustrates a plurality of stiffeners 40 welded to the structural tube steel member 15 and the end plate 10 illustrated in FIG. 1. In FIG. 3, for example, four stiffeners 40 (only three of which are shown) arc welded to outside faces of the structural tube steel member 15. In the conventional art, the stiffeners 40 could induce relatively high local stresses in the structural tube steel member 15 in the event a relatively large bending moment is applied to the structural tube steel member 15. Thus, in the conventional art, plates are often provided between the stiffeners and the member to which they attach for stress reduction.
In FIGS. 1-3, the structural tube steel member 15 is shown as having a single end plate 10 at one end only, however, as one skilled in the art would understand, conventional tube steel members are often constructed with plates arranged at both ends of the structural tube steel member. For example, as shown in FIG. 4, a structural tube steel member 50 may have a first end plate 55 arranged at a first end of the structural tube steel member 50 and a second end plate 60 arranged at a second end of the structural tube steel member 60. As in the previous example, the first and second end plates 55 and 60 may be welded to the tube steel member 50. The structural tube steel member 50 of FIG. 4 may be substantially the same as the structural tube steel member 15 as shown in FIG. 3 and the first and second end plates 55 and 60 may be substantially the same as the end plate 10 illustrated in FIGS. 1-3. Furthermore, while not shown in FIG. 4, the stiffeners 40 illustrated in FIG. 3 may be attached at the interfaces between the structural tube steel member 50 and the first and second end plates 55 and 60 in the same manner as they are attached to the structural tube steel member 15 and the end plate 10 as shown in FIG. 3.
FIG. 5 represents a conventional frame having a first column 70 and a second column 75 connected by bracing 80. As shown in FIG. 5, the first and second vertical columns 70 and 80 may be constructed by attaching, end-to-end, structural tube steel members that have end plates provided at both ends. In this conventional example, the end-to-end structural tube steel members may be substantially the same as the structural tube steel member 50 with end plates 55 and 60 as shown in FIG. 4. Each of the structural tube steel members may be secured to each other via a plurality of bolts 85. The bracing 80 may be steel members such as angle iron, and the bracing 80 may be attached to the columns 70 and 80 by a series of tabs 90 which are welded to outside surfaces of the structural tube steel members. In the conventional art, the tabs 90 are offset from the end plates and resemble a plate with a hole to allow the bracing to be pinned thereto.
In the conventional art, welding plates (for example, stiffener plates and end plates) to structural tubing members is relatively expensive. Furthermore, directly welding a stiffener plate and tabs to an outside surface of a structural tube member renders the structural tube member vulnerable to relatively high stresses.